Helical Bed Biofilm Reactor for Wastewater Treatment

Abstract

The disclosure herein relates to a helical bed biofilm reactor for wastewater treatment, and belongs to the fields of environment engineering and chemical engineering. The helical bed biofilm reactor comprises a reaction vessel, a draft tube, helical screen meshes, carriers, a carrier passage, a gas distributor, a gas inlet, a gas outlet, a water inlet, a water outlet and a sludge outlet. By improving the arrangement structure of the carriers and the structure of the helical passage, the helical bed biofilm reactor improves the oxygen transfer rate, the oxygen transfer efficiency and the biological reaction efficiency of a biological treatment process of wastewater, and helps to control the thickness of the biofilm and reduce energy consumption in wastewater treatment.

What is claimed is: 
     
         1 . A helical bed biofilm reactor, comprising a vessel, a draft tube, carriers and carrier passages, wherein a gas outlet is arranged at a top of the vessel; a sludge outlet is arranged at a bottom of the vessel; a water outlet and a water inlet are arranged on a side wall of the vessel; the water outlet is positioned above the water inlet; a draft tube is positioned inside the vessel and is arranged coaxially with the vessel; a height of the draft tube is smaller than a height of the vessel; an upper part of the draft tube is communicated with the water inlet; the carrier passage is positioned inside the vessel and is arranged helically along an outer side of the draft tube; the carrier passage is composed of upper and lower helical screen meshes; two side edges of each layer of the screen mesh are fixed to an inner-side wall of the vessel and an outer-side wall of the draft tube, respectively; the carrier passage is internally filled with the carriers; and a no-load passage is formed between adjacent carrier passages. 
     
     
         2 . The helical bed biofilm reactor according to  claim 1 , wherein the vessel is provided with a carrier inlet and a carrier outlet; the carrier inlet is arranged at an upper part of the outer side of the vessel, and is horizontally connected with the highest point of the helical screen meshes; the carrier outlet is positioned at a lower part of the outer side of the vessel, and is connected with the lowest point of the helical screen meshes in a horizontal direction; flat screen meshes are arranged at the carrier inlet and the carrier outlet, respectively; and the flat screen meshes are connected and fixed to the two upper and lower helical screen meshes of the carrier passage. 
     
     
         3 . The helical bed biofilm reactor according to  claim 1 , wherein the carrier is composed of a carrier shell and an inner core carrier; the inner core carrier is arranged inside the carrier shell and is not fixed to the carrier shell; the carrier shell is a mesh-like sphere; the inner core carrier is a carrier with brush-like protrusions on a surface or a polygonal carrier with through holes inside; and when the reactor is in operation, the inner core carrier tumbles in spherical carriers under hydraulic action. 
     
     
         4 . The helical bed biofilm reactor according to  claim 3 , wherein the vessel is provided with a carrier inlet and a carrier outlet; the carrier inlet is arranged at an upper part of the outer side of the vessel, and is horizontally connected with the highest point of the helical screen meshes; the carrier outlet is positioned at a lower part of the outer side of the vessel, and is connected with the lowest point of the helical screen meshes in a horizontal direction; flat screen meshes are arranged at the carrier inlet and the carrier outlet, respectively; the flat screen meshes are connected and fixed to the two upper and lower helical screen meshes of the carrier passage; and the carrier inlet and the carrier outlet are each led out to the outer side of the vessel. 
     
     
         5 . The helical bed biofilm reactor according to  claim 3 , wherein the inner core carrier has a structure selected from a group consisting of a honeycomb, a spongy, a foam-like structure and a brush-like structure. 
     
     
         6 . The helical bed biofilm reactor according to  claim 4 , wherein a diameter of the carrier shell is 50-100 mm; a size of the inner core carrier is smaller than the diameter of the carrier shell and larger than a pore diameter of the carrier shell; and the inner core carrier has a structure selected from a group consisting of a honeycomb, a spongy, a foam-like structure and a brush-like structure. 
     
     
         7 . The helical bed biofilm reactor according to  claim 6 , wherein the carrier inlet and the carrier outlet are each a rectangle; a height of the rectangle is equal to a vertical height of a side passage of the carriers; and the carrier inlet and the carrier outlet adopt a square vertical hanging cover hubbed flange manhole on the outer side of the vessel. 
     
     
         8 . The helical bed biofilm reactor according to  claim 6 , wherein a gas distributor is arranged below the draft tube, and the gas distributor is one selected from a group consisting of: a looped tube gas distributor; a plurality of nozzles arranged in a circumferential direction; an aeration tube containing a plurality of micropores; and an aeration disc containing a plurality of micropores. 
     
     
         9 . The helical bed biofilm reactor according to  claim 8 , wherein the helical screen meshes have equal pitches, and the number of the helical screen meshes is even. 
     
     
         10 . The helical bed biofilm reactor according to  claim 8 , wherein a spacing between adjacent helical screen meshes is the same or different. 
     
     
         11 . The helical bed biofilm reactor according to  claim 8 , wherein a helical surface of the helical screen mesh is one selected from a group consisting of: a positive helical surface; an inwardly inclined helical surface; and an outwardly inclined helical surface. 
     
     
         12 . The helical bed biofilm reactor according to  claim 8 , wherein a material of the helical screen mesh is a material selected from a group consisting of plastic, nylon, composite non-metallic materials, and lightweight metal alloy materials. 
     
     
         13 . The helical bed biofilm reactor according to  claim 8 , wherein a ratio of a distance between the lowest point of the helical screen meshes in a vertical direction and a bottom of the draft tube to an inner diameter of the vessel is 0.1-0.6; and a ratio of a distance between the highest point of the helical screen meshes in the vertical direction and a top of the draft tube to the inner diameter of the vessel is 0.1-0.5. 
     
     
         14 . The helical bed biofilm reactor according to  claim 8 , wherein a free area ratio of the helical screen mesh is 60%-90%, and a mesh hole is smaller than a diameter of the carrier. 
     
     
         15 . The helical bed biofilm reactor according to  claim 1 , wherein a height-to-diameter ratio of a cylinder part of the vessel of which an inner space is provided with a gas-liquid mixing zone is (2:1)-(6:1); an inner diameter of the gas-liquid separation zone is not less than an inner diameter of the vessel; and a ratio of a cross-sectional area of an riser section of the vessel to a cross-sectional area of a downcomer section is (1:0.3)-(1:1). 
     
     
         16 . The helical bed biofilm reactor according to  claim 6 , wherein the helical screen meshes have equal pitches; the number of the helical screen meshes is even; a spacing between adjacent helical screen meshes is the same; the spacing between the adjacent helical screen meshes is 5%-50% of the pitch of the helical screen mesh; a helical surface of the helical screen mesh is one selected from a group consisting of a positive helical surface, an inwardly inclined helical surface, and an outwardly inclined helical surface; a free area ratio of the helical screen mesh is 60%-90%; a pore diameter of the helical screen mesh is 10-50 mm; and a material of the helical screen mesh is selected from a group consisting of plastic, nylon, composite non-metallic materials, and lightweight metal alloy materials. 
     
     
         17 . The helical bed biofilm reactor according to  claim 1 , wherein the helical bed biofilm reactor is an atmospheric pressure vessel, or a pressure vessel. 
     
     
         18 . A method for wastewater treatment by using the helical bed biofilm reactor according to  claim 1 , comprising inoculating sludge into the helical bed biofilm reactor; feeding in wastewater; and causing the helical bed biofilm reactor to operate for at least 30 days. 
     
     
         19 . A method for wastewater treatment by using the helical bed biofilm reactor according to  claim 16 , comprising inoculating sludge into the helical bed biofilm reactor; feeding in wastewater; and causing the helical bed biofilm reactor to operate for at least 30 days.